# CAT-21

URL: https://blockspace.wiki/glossary/cat-21/

A protocol whose mint is any transaction with `nLockTime = 21`. In BTI the cat is a label; the token is the first sat of output 0, a sat in the Ordinal Sats family, catalogued by the ord adapter. The locktime field exists in every transaction, so the data-types reference says the channel costs no extra bytes.

Sources:

- Blockspace Holdings records
- block.space docs: data types · https://block.space/docs/datatypes

Updated: 2026-10-20